onlinemetals.com
They sell small quantities without charging an arm and a leg. A quick search showed 3" 6061-T6 schedule 40 aluminum pipe at 3ft length for around $50 with an additional $17ish for shipping to VA.
Like Alan mentioned though, Pipe "sizes" don't always match actual dimensions (3.5" outer diameter for the above mentioned 3" pipe). They are pretty clear about that on the site though, showing the inner and outer tube diameters. You could hunt around in their tubing and pipe sections under the metal of your choice (aluminum of various flavors, stainless, cold roll, etc) and probably find something that suits your needs without breaking the bank.
Also, dumpster diving. Probably a full third of the Virginia Tech Ground Station metalwork was harvested from a metal dumpster outside a machine shop on campus (including some solid piping for our dish mounts and some of the counter weighting metals). Just be safe about it, I got the OK from the machine shop folks and campus security folks to pull stuff out of the dumpster (some places take dumpsters like that in for a cash return at recycling centers and such, so taking what looks like 'trash' is actually money out of their pocket).
Good Luck!
-Zach, KJ4QLP
Research Associate Ted & Karyn Hume Center for National Security & Technology Virginia Polytechnic Institute & State University Work Phone: 540-231-4174 Cell Phone: 540-808-6305
On 5/9/2016 5:25 PM, Daniel Cussen wrote:
I would second the idea of getting a local welder or engineering shop to make up something suitable. If possible send it off for galvanising which they can do too.
Note many of these larger dishes are not designed to use normal TV LNBs but are instead intended to use special manufacturer feeds, and they use unusual designs. Using the wrong feed will reduce the results.
Here is information on the recommended installation in a fixed mount including concrete base.
http://viasatelital.com/manuales/channel_master/channel-master-type-120.pdf
If you are not using it in a fixed position, but for low earth orbit tracking on s-band, like I am, I can give more advice. I am using a 1.2 metre dish. In particular the modification for larger feeds, calibration due to offset feed and real world low earth orbit tracking problems.
If you can supply photos of links of the actual dish we may be able to help further. _______________________________________________ Sent via AMSAT-BB@amsat.org. AMSAT-NA makes this open forum available to all interested persons worldwide without requiring membership. Opinions expressed are solely those of the author, and do not reflect the official views of AMSAT-NA. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://www.amsat.org/mailman/listinfo/amsat-bb